SELECTION OF PEAT LANDS FOR DIFFERENT USES 15 
tion of the compressive strength of layers for different types of peat 
areas or a description of peat nraterials and their mechanical proper- 
ties that would enable one to identify them with those from other 
locations. It would greatly benefit highway research if field investi- 
gations on this vital problem could be supplemented by laboratory 
tests, because the relation which exists between the strength in ten- 
sion and compression of different types of peat and the bearing ca- 
pacity of the same material at critical moisture contents is not yet 
nown. 
The stratigraphic classification of peat lands is of advantage also 
in determining what proportion of the peat-land resources may be 
devoted particularly to the development of improved varieties in 
crops or planned with respect to the better combination of crops, 
including shrubs and forest trees (5,20). There is no reason os 
carefully selected regional areas of peat land should not produce 
cereals, seeds, grasses, clovers, sugar beets, and textile plants as well 
as truck crops or pasture for beef cattle and wool-growing sheep. In 
many instances, reforestation of certain types of peat land could be 
practiced much more extensively than has been done in the past, and 
industries utilizing peat materials could make marked contribution 
toward the production of stable litter and composts. Iurthermore, 
knowledge of the structural framework will aid in developing the 
proper organizations among communities, especially of a cooperative 
character, for growing erops on a large scale or for advancing the spe- 
cialization in farming and industry ot may be desirable on complex 
types of peat land. 
THE WATER TABLE AND ITS EFFECTS 
Water is the outstanding physical condition affecting the origin 
of different peat materials and the formation of the profile structure 
of different types of peat land. The predominating surface vegeta- 
tion generally indicates the effect of water content rather than the 
character of the peat soil. The thickness, number, and quality of 
sedimentary layers of peat definitely show correlation with high 
standing-water levels, while the accumulations of woody or fibrous 
peat layers correspond to a diminishing or fluctuating supply of mois- 
ture. When a wooded or marshy peat-land area is resubmerged or 
held in a wet condition for an indefinite period it reverts to the for- 
mation of a sedimentary layer of peat. 
An insufficient knowledge of the effects of the water table has been, 
apparently,in most cases the reason why many farmers, manufacturers 
of peat products, and even drainage and highway engineers have met 
with frequent difficulties. Differences in the structural framework 
of peat lands have an important bearing upon estimating the drainage 
capacity of an area. They show very definitely, too, the respective 
need for a system to irrigate with free water or to control the mode 
of supply of soil moisture. How stratigraphic features may affect 
and in turn become affected by drainage or irrigation has not yet 
been given due attention. i } 
An examination of profiles 2-1-2, 2-1-3, or 3-1-3 in Plate 1 will 
help to explain why sedimentary layers of peat may become dis- 
placed or protrude into drainage channels. On account of the pres- 
sure of heavy loads. such as a sand cover, a hichway roadbed, or a